Redirect CP/M console (SC131)

[Frank P.]

I've found out that when booted into CP/M 3.0, I can switch console I/O to serial port B at 38400 baud this way (typed into serial port A after CP/M 3.0 boot):

mode com1: 38400

device console=com1

Is there any way to do this in CP/M 2.2 or via RomWBW, or is this strictly a CP/M 3.0 capability?

[Douglas Miller]

Redirection depends on support in the BIOS. I'd assume that if Wayne supports it in CP/M 3 that he also supports it in CP/M 2.2. But, the device names and assignments are different. See documentation on the STAT utility ("STAT VAL:" and "STAT DEV:" specifically), and maybe Wayne or someone else will jump in and report the details for RomWBW systems.

[Wayne Warthen]

Sure.  Instead of the "device console=com1" command, you can use "stat con:=uc1:" under CP/M 2.2 or ZSDOS.  The "mode" command is the same for any OS that RomWBW supports.

Note that CP/M 2.2 has a fairly arcane way of identifying devices.  Although UC1: refers to the second serial port, it is not the case that UC2: refers to the third serial port.  In fact, there is no UC2: under CP/M 2.2.  If you want to learn more about CP/M 2.2 port redirection, look for information on IOBYTE in the CP/M 2.2 Manual (which is included with RomWBW in the Doc directory).

-Wayne

 

[Frank P.]

Perfect, Wayne! And "stat con:=tty:" changes it back to port A.

Curiously, if I change con: to port B, and initiate an XM R transfer from there, it still expects the XMODEM transfer to take place on port A. I guess XM.COM is hard coded to tty: .

[Wayne Warthen]

On Sunday, April 18, 2021 at 3:13:23 PM UTC-7 Frank P. wrote:

Perfect, Wayne! And "stat con:=tty:" changes it back to port A.

Curiously, if I change con: to port B, and initiate an XM R transfer from there, it still expects the XMODEM transfer to take place on port A. I guess XM.COM is hard coded to tty: .

It is more accurate to say that XM talks directly to HBIOS serial ports.  By default, this is the HBIOS console.  The HBIOS console is determined at boot and is not changed when you redirect using CP/M.

If you want to try using the dev branch of RomWBW, XM has been enhanced to allow specifying any of the HBIOS serial ports on the command line.  You just append the number of the character unit to the action letter.  So, for example, you could use XM R2 <filename> to receive a file from character unit 2 (the third serial port).

-Wayne 

[Frank P.]

Grabbed and built that version of XM but it apparently needs the newer RomWBW BIOS, and I'm afraid I'm not quite that adventurous. Good to know though if I ever want to undertake a complete upgrade of the SC131. For right now, it's just cool to be able to switch the console between ports in CP/M. Thanks Wayne!